It is the continued pulling back of the hair that causes what's called "traction allopecia" and I don't think it has to be too tight (although that certainly accelerates it) for that to happen as it appears the hairline hairs are very sensitive.

A receding hairline is very common among women who have chemically straightened their hair for many years as even minor burns from relaxers can cause permanent death of the follicles, it's usually the "wake-up" call that makes many women stop and go natural.

I suspect that women who thermally straighten daily (or have done so) may have a similar problem as it's hard to not occasionally touch the skin with the hot tool when trying to get the hairline completely smooth. I still remember how I burned myself a few times when using a curling iron on the front in a hurry before going to work years ago...!
2A/3A, medium length, layered, colored dark/medium ash blonde - "CGer" since April '02.

"Converting the 'curlskeptics' one curly head at a time..." HWHC